The efficient separation of fluids of different density is central to the efforts of industry to improve our environment by reducing the pollutants entering the atmosphere and to maintain the safety of working environments. Typical of such materials are such things as iron and steel furnace fumes and dust, ground limestone, carbon black, H.sub.2 SO.sub.4 mists, pulverized coal, pigments, oil smoke, fly ash, foundry dust, alkali fumes, metallurgical fumes and dust, magnesium oxide smoke, zinc oxide fumes and the like.
Some of these can be separated by means of dry mechanical collectors such as a settling chamber, cyclone, fabric collector (bag filter) and electrostatic precipitator. Others must be separated by means of a wet scrubber such as a spray tower, packed tower, flooded mesh scrubber, reverse jet scrubber, wet cyclone, venturi or orifice scrubber.
Frequently, wet and dry collectors are combined, e.g., by (1) scrubbing gases containing a dispersion of either fluid or solid particulate matter with a liquid and then (2) separating the resulting dispersed liquid phase in an inertial separator, such as a cyclone or vane demister.
One important consideration in the design and use of separator systems is the physical space which is available for the system. For example, any machine mounted system for the removal of coal dust from the air at the face of a coal mine must be extremely compact in order to be able to fit on a conventional mining machine. Thus, countercurrent, non-atomizing scrubbers, because of their large space requirements, cannot be used in this application. On the other hand, compact co-current atomizing scrubbers with separators which would meet the limited space requirements tend to incur re-entrainment.